"It woke up almost everybody in the house," said Albert Dicochea, a Fremont resident.

"It was on the Hayward fault, which is large fault that we expect to rupture in the next big earthquake. Since then, there have been 14 aftershocks, the largest which was a magnitude 2.7," explained AnneMarie Baltay with the U.S. Geological Survey.

@abc7newsBayArea and peeps..don't forget to report that you felt it on the USGS site. Short survey.

Meanwhile, there were some delays on BART. Around 4:30 a.m., BART reported 30-minute delays as the tracks were inspections. Just before 5 a.m., all of the tracks had been inspected and trains returned to normal speed.

The quakes come nearly a year after a magnitude 6.0 earthquake struck the region. The August 2014 quake was the largest to hit Northern California in a quarter-century. That quake killed one woman and caused about $400 million in property damage in Napa Valley.